1a.Objectives (from AD-416)
Determine how fructan profiles in orchardgrass and bermudagrass forages are affected by the time of year in which they are grazed (early vs. late in the growing season), as well as by time of day.

1b.Approach (from AD-416)
Orchardgrass and bermudagrass samples, collected in Virginia during the spring and late summer (mid-April to late August) will be analyzed for fructan content. Fructans will be extracted from the samples with boiling water and analyzed by anion-exchange high-performance liquid chromatography (HPLC) coupled to pulsed amperometric detection (PAD). Profiles will be compared to those of a sample harvested at the optimal growth stage to determine how seasonal and diurnal variations affect the relative changes in amounts and types of fructans in the forages.

3.Progress Report

Performance of this agreement is monitored by USDA-ARS, (Forage-Animal Production Research Unit) FAPRU scientists being involved as collaborators in the agreement project, and meeting with the collaborator on an as needed basis to alter experimental design. Information exchange and planning is via face to face meetings, teleconferences or email. Progress has been made on this project. The goal of this project is to better understand the relationship between environmental stress on forages, the resultant production of fructans and forage induced laminitis in horses. Of 256 orchardgrass and bermudagrass samples, all but one extract has been analyzed at FAPRU by high-performance liquid chromatography coupled to pulsed amperometric detection. Glucose, fructose, sucrose, and total long-chain fructans have been quantified for each sample. Tables of results, and chromatograms, have been provided to collaborators. Results still need to be analyzed in terms of the field study, and that analysis will be conducted by the Virginia Tech collaborators, who conducted the field study. A poster of the relationship between HPLC data and colorimetric assays for ethanol- and water-soluble carbohydrates (WSC and ESC) was presented at the 2009 Southern Pasture and Forage Crop Improvement Conference (SPFCIC) in Lexington, KY.